Gekidan Inu Curry are an animation troupe famous for their designs of the witches and the witches’ otherworld in Puella Magi Madoka☆Magica. Their techniques draw inspiration from Russian animation and Czech animation. They utilize stop-motion animation and coloring that resembles hand-drawn illustrations.
Their pen names are 2shiroinu (2白犬) and Doroinu (泥犬). 2shiroinu, or Ayumi Shiraishi (白石 亜由美), is a former Gainax animator. Doroinu, or Yousuke Anai, worked at Tanto Do-GA Studio. (source)